Disclosed in U.S. Patent Publication No. 2007/0012327, incorporated herein by reference, is a cigarette filter subassembly which comprises a first cylindrical cellulose acetate absorbent member defining a first end surface, with the first end surface of the first absorbent member forming a first end of the cigarette filter subassembly. A second cylindrical cellulose acetate absorbent member defines a second end surface, with the second end surface of the second absorbent member forming a second end of the cigarette filter subassembly. At least one capsule is provided between the first absorbent member and the second absorbent member with the capsule(s) containing a releasable additive material for modifying characteristics of tobacco smoke during smoking of the cigarette. The capsule(s) releases at least a portion of the releasable material when subjected to external force. The cigarette filter subassembly has an outer cover extending substantially from the first end of the cigarette filter subassembly to the second end of the cigarette filter subassembly and encloses the capsule(s). The outer cover is formed of a material which is substantially impermeable to the releasable material of the capsule(s).
A method for manufacturing those cigarette filter subassemblies comprises the steps of: providing a series of absorbent members; providing at least one capsule between adjacent absorbent members with the capsule(s) containing a releasable material for modifying characteristics of tobacco smoke during smoking of the cigarette. The capsule(s) releases at least a portion of the releasable material when subjected to external force. The method further comprises the step of providing an outer cover about the series of absorbent members and the capsule(s). The outer cover is formed of a material which is substantially impermeable to the releasable material of the capsule(s). An annular layer of cellulose acetate is then formed about the outer cover of the cigarette filter subassembly.
There is an interest in an improved method for making the cigarette filter subassembly.